Chosen Solution
The left USB port in my MacBook Air got bent and no USB drive would go in. I tried to fix it myself by opening up the Mac using help from this forum posts. Ended up with not only the problem unresolved ( the aluminium part is too twisted to correct) but now audio device is not detected, fan has started whirring at high speed and the MagSafe adapter doesn’t light up ( charges normally though). Help!
Try reseating the I/O board cable and the other relevant cables as shown in this guide: MacBook Air 13" Early 2015 I/O Board Replacement Might be a silly question but have you made sure the I/O cable is not plugged upside down where it would cover the fan?
